Filtration device and method

ABSTRACT

In one example, we describe a method and system that uses iron oxide as its sole sorbent, specifically micron-sized nano-porous iron oxide particles. The sorbent is housed inside a horizontally rotating sorbent bed. The horizontally rotating sorbent bed is housed inside of a larger secondary compartment. At the top of the secondary compartment, there is an escaped sorbent particle containment membrane. One example uses a self-cleaning horizontally rotating sorbent drum membrane design that unclogs particulates lodged in the membrane by reversing particulate air flow direction during a small portion (e.g., about 20 degrees) of each full 360 degree rotation of the drum. When air flow passes through the porous horizontally rotating sorbent drum&#39;s membrane, which occurs at the location where the rotating sorbent bed membrane comes into contact with the air feed manifold, particulates are air-dislodged from the inner facing surface of the drum&#39;s membrane. Other variations are discussed.

BACKGROUND OF THE INVENTION

The filtering for fluid, including liquid and gas, is extremelyimportant for multiple reasons, including, e.g., for recycling,environmental cleaning, toxic removal, drinking water, allergyreduction, gathering precious material, filtering specific material,semiconductor processing and production, purification, medical reasons,medical supplies, laboratory work, experimental parameter control, andstandardization. One aspect of filtering is removal of particles orsubstances from the fluid, such as from air.

Air filters are used to remove impurities from air. Such air filterstypically include a removable and replaceable main filter cartridgepositioned therein. The main filter cartridge can be connected to asecondary filter, and multiple filters thereafter. Filter cartridges aretypically serviced by being removed or replaced.

Some of the prior work is described in the following US and foreignpatents/applications:

6,358,871 Sircar 6,923,841 Chen 20050126428 Lee, et al. 7,141,518MacDonald, et al. 20090252654 Hsu, et al. 20100233245 Narayana20110036778 Willuweit JP 1998173766 Ohtake, et al. JP 10130072 Miyao JP11019431 Iimura, et al. JP 2000157811 Yamamoto JP 2002331212 Ogawa CN101020133 Sun, et al. JP 4212927 Miwa, et al. WO 2009059457 Chen, et al.TW 337632 Chen, et al. JP 4692311 Ueda DE 102010005114 Scope, et al.

An example of journal publication is: CAI, et al., “Effect of molarratio of MgO/Al2O3 on the performance of MgO—Al2O3-Fe2O3 composite,”Advanced Materials Research, Pt. 1, Materials and Design, pp. 242-245,2011.

However, the invention and embodiments described here, below, have notbeen addressed or presented in any prior art. For example, oneembodiment teaches a filter apparatus, specifically a filter apparatusfor air filtration of airborne particulates, using a sorbent.

For some of the prior art, iron oxide is one of the multiple compoundslisted that collectively comprise the sorbent. However, iron oxide alonehas not been used as the single or sole compound for sorbent. Forexample, for JP 2000157811, ceramic is impregnated or otherwise combinedwith iron oxide. Ceramic and iron oxide together comprise the sorbent.For JP 4212927, iron oxide is a catalyst for particulate removal fromdiesel engine exhaust.

In one embodiment of our invention, a sorbent air filtration device isdisclosed. The sorbent is comprised solely and exclusively of ironoxide, specifically micron-sized nano-porous iron oxide particles.

SUMMARY OF THE INVENTION

In one embodiment, we describe a method that uses iron oxide as its solesorbent, specifically micron-sized nano-porous iron oxide particles. Thesorbent is housed inside a horizontally rotating sorbent bed. Thehorizontally rotating sorbent bed is housed inside of a larger secondarycompartment. At the top of the secondary compartment, there is anescaped sorbent particle containment membrane.

The mechanism of filtration in a horizontally rotating sorbent bed isdifferent from vertically rotating cyclonic air filters. A horizontallyrotating sorbent bed uses horizontal rotation to uniformly disbursesorbent particles in the air flow, so to prevent particulateagglomeration or clustering or clogging that reduces sorbent capacityand operational life. Therefore, a horizontally rotating sorbent bed isa particle dispersion mechanism. In contrast, a vertically rotatingcyclonic air filter uses vertical rotation to centrifugally segregateparticulates from air. Therefore, a vertically rotating cyclonic airfilter is a particle segregation mechanism.

Typical air filter membranes are subject to membrane clogging, alsoknown as membrane fouling, which occurs when particulates become lodgedin and obstruct membrane apertures. Membrane particulate cloggingimpedes air filter performance by reducing the volume of remainingfunctional membrane surface area available for particle filtration.

One embodiment of this invention uses a self-cleaning membrane designthat unclogs particulates lodged in the membrane by reversingparticulate air flow direction during a small portion (about 20 degrees,as an example) of each full 360 degree rotation of the sorbent bed. Whenair flow passes through the rotating sorbent bed membrane, which occursat the location where the rotating sorbent bed membrane comes intocontact with the air feed manifold, particulates are air-dislodged fromthe inner facing surface of the membrane. During the remainder of thecycle, air flow pushes particulates up against the inner facing surfacemembrane, which causes particulate lodging. Particulate lodging onlyoccurs when the size of the particulate coming into contact withmembrane is exactly or near the same size as the membrane's aperture.

Particulates larger than the membrane's aperture remain contained insidethe rotating sorbent bed. Particulates smaller than the membrane'saperture escape through the rotating sorbent bed membrane and travelupwards inside the larger secondary compartment. Located at the top ofthe secondary compartment is an escaped sorbent particle containmentmembrane. The surface area of the escaped sorbent particle containmentmembrane is larger than the 2-dimensional surface area at the bottom ofthe secondary compartment, to reduce backpressure and air flow speed.The secondary sorbent can be alumina, zeolites, sulfur, activatedcarbon, or any combination thereof, depending on the type of particlestargeted for remediation or filtering purpose.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is for one embodiment, as an example, for the whole apparatus.

FIG. 2 is for one embodiment, as an example, for the cross section ofthe horizontally rotating sorbent drum.

FIG. 3 is for one embodiment, as an example, for the cross section ofthe horizontally rotating sorbent drum.

FIG. 4 is for one embodiment, as an example, for the cross section ofthe horizontally rotating sorbent drum.

FIG. 5 is for one embodiment, as an example, for the cross section ofthe horizontally rotating sorbent drum.

FIG. 6 is for one embodiment, as an example, for series configuration ofhorizontally rotating sorbent drums and filters or membranes.

FIG. 7 is for one embodiment, as an example, for parallel configurationof horizontally rotating sorbent drums and filters or membranes.

FIG. 8 is for one embodiment, as an example, for series/parallel mixedconfigurations of horizontally rotating sorbent drums and filters ormembranes.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In one embodiment of the invention, air enters the filter through a pump[1]. The pump pushes air through an air feed hose [2] into an airreservoir compartment [3]. The air reservoir compartment is the internalarea of a protective housing shell [4] that is located directly below ahorizontally rotating sorbent drum [5].

In one embodiment of the invention, the horizontally rotating sorbentdrum's outer layer is a porous membrane comprised of wire cloth [6]. Thehorizontally rotating sorbent drum's inner cavity contains sorbentparticles. The horizontally rotating sorbent drum rotates on a spindle[7] that is connected to a motor [8]. A motor brace [9] anchors themotor to the top of the protective housing shell. Also attached to thetop of the protective housing shell, directly above the air reservoircompartment, is a secondary compartment [10]. At the top of thesecondary compartment is a secondary membrane filter [11].

In one embodiment of the invention, air pumped inside the air reservoircompartment exits the air reservoir compartment through a narrowrectangular slot located at the top center of the air reservoircompartment. The narrow rectangular slot's length [12] is approximately98% the length of the horizontally rotating sorbent drum, as an example,for uniform air dispersion. Two grooves [13], one on each end of thehorizontally rotating sorbent drum, upon which the drum rests upon whenrotating, comprise the remaining, approximate 2%, of the narrowrectangular slot's length (See FIG. 1).

In one embodiment of the invention, the region of the protective housingshell located directly to the left and right of the narrow rectangularslot, upon which the horizontally rotating sorbent drum rests, isconcave shaped [14] to minimize air flow leakage and rotationalresistance.

In one embodiment of the invention, as the upward traveling air exitsthe air reservoir compartment and passes through the horizontallyrotating sorbent drum's porous wire cloth membrane, air comes intocontact with sorbent particles that have accumulated at the bottom ofthe horizontally rotating sorbent drum. The air flow separatesaccumulated sorbent particles resting at the bottom of the horizontallyrotating sorbent drum [15] and pushes the particles upwards [16] insideof the horizontally rotating sorbent drum's inner cavity. As sorbentparticles are pushed higher inside the rotating sorbent drum's innercavity, particulate agglomerations become smaller and smaller (See FIG.2).

In one embodiment of the invention, this separation process causessorbent particles, as they travel upward and outward, to continuouslyrotate and reorient their position inside the horizontally rotatingsorbent drum, which in turn exposes particle surface areas, previouslyunexposed to contaminants in an air flow, to become exposed to andcapture contaminants, whereby increasing sorbent capacity and lifecycle, as well as increasing effective cross section area or outersurface area exposed to contaminants, to capture more contaminants,faster and more efficiently, with less cost of maintenance, repair,cleaning, supplies, and down-time, reducing the overall cost ofequipment for installation and maintenance.

In one embodiment of the invention, for sorbent particles larger than 10microns, as an example of the threshold and size for the drum parameterand dimension, when they come into contact with drum membrane's innerfacing wall, they lose their velocity and fall back to the bottom of thedrum [17] (See FIG. 3).

In one embodiment of the invention, sorbent particles equal to or near10 microns become lodged in drum membrane's inner facing wall [18], andare later dislodged from membrane [19], as previously described (SeeFIG. 4).

In one embodiment of the invention, sorbent particles smaller than 10microns escape through drum membrane [20], as previously described (SeeFIG. 5).

In one embodiment of the invention, the membrane of the horizontallyrotating sorbent bed is wire cloth, sintered metal, or similar porousmetal. The sorbent bed rotates on a spindle or spin device that isconnected to a motor, directly or through a gear box or gear or belt orchain or shaft. A motor brace anchors the motor to a base plate.

In one embodiment of the invention, the air feed manifold reconfiguresthe air flow, from a cylindrical shape equal to the inner diameter ofthe pump's air output hose to a thin rectangle shape equal to thehorizontal length of the rotating sorbent bed, for uniform air flowdispersion.

In one embodiment of the invention, flexible blades create a flexiblebarrier between the air feed manifold and the horizontally rotatingsorbent bed, and are angled at approximately 10 degrees, as an example,in the same direction as sorbent bed's rotation, so that air travelsdirectly from the manifold to the rotating sorbent bed's outer facingmembrane with (a) little to no air flow leakage, and (b) minimalresistance to the sorbent bed's rotation. In one embodiment of theinvention, the air flow that passes through the rotating sorbent bed'smembrane enters the internal cavity of the sorbent bed at the bottom ofthe horizontally rotating sorbent bed.

In one embodiment of the invention, as the upward traveling air flowcomes into contact with sorbent particles that have been accumulated atthe bottom of the rotating sorbent bed, accumulated sorbent particlesseparate from the bottom mass and are pushed upwards. As sorbentparticles are pushed higher, inside the rotating sorbent bed's innercavity, particulate agglomerations or accumulations become smaller andsmaller, for more efficient filtering and less clogging effect. Thisincreases sorbent capacity and life cycle. This increases efficiency andfiltering output, reducing the price and cost for the process anddevice, as well as reducing the maintenance frequency and cost.

In one embodiment of the invention, the horizontally rotating sorbentbed itself is housed inside of a larger secondary sealed compartment(see FIG. 1). Air flow containing sorbent particles smaller than 10microns travel upwards in the compartment until they reach an escapedsorbent particle containment membrane [11], located at the top of thecompartment. The secondary filter contains a secondary membrane, filter,and/or sorbent bed component that captures particles less than 10microns (as an example) in the airstream that escaped through theprimary rotating sorbent bed. The surface area of the escaped sorbentparticle containment membrane [11] is larger than the 2-dimensionalsurface area at the bottom of the secondary compartment, slowingparticulate and air flow velocity (as shown in FIG. 1).

Here are some examples for our inventions, with the specific obtainedresults:

Example 1

An air flow containing multi-element particles was introduced into ahorizontally rotating sorbent bed comprising a nano-porous iron oxidesorbent. An ICP/MS analysis confirmed that the nano-porous iron oxidesorbent filtered all particles which comprised sodium, magnesium,phosphorus, potassium, manganese, cobalt, nickel, copper, zinc, andgold.

Example 2

An air flow containing multi-element particles was introduced into ahorizontally rotating sorbent bed comprising a nano-porous iron oxidesorbent. An ICP/MS analysis confirmed that the nano-porous iron oxidesorbent filtered particles which comprised sodium, magnesium, aluminum,potassium, calcium, titanium, manganese, cobalt, nickel, copper, andlead.

Example 3

An air flow containing multi-element particles was introduced into ahorizontally rotating sorbent bed comprising a nano-porous iron oxidesorbent. An ICP/MS analysis confirmed that the nano-porous iron oxidesorbent filtered particles which comprised sodium, magnesium, aluminum,potassium, calcium, titanium, manganese, cobalt, nickel, copper, zinc,and gold.

Example 4

An air flow containing particles was introduced into a horizontallyrotating sorbent bed comprising a nano-porous iron oxide sorbent. A dualelement ICP/MS analysis confirmed that the nano-porous iron oxidesorbent filtered particles of arsenic and lead.

Example 5

An air flow containing particles was introduced into a horizontallyrotating sorbent bed comprising a nano-porous iron oxide sorbent. Asingle element ICP/MS analysis confirmed that the nano-porous iron oxidesorbent filtered particles of silver.

In various embodiments, we have the following variations and situations:

-   -   A device comprising an air filter that uses iron oxide as        device's sole sorbent, housed in a horizontally rotating sorbent        bed.    -   The iron oxide sorbent is nano-porous.    -   The iron oxide particle size ranges from 5 to 90 microns.    -   The mean iron oxide particle size is 21 microns.    -   The average iron oxide particle size is 21 microns.    -   The standard deviation for iron oxide particle size is 2        microns.    -   The standard deviation for iron oxide particle size is 5        microns.    -   The standard deviation for iron oxide particle size is 10        microns.    -   The standard deviation for iron oxide particle size is 20        microns.    -   The iron oxide particle size surface area ranges from 50 to 400        m²/gram.    -   The iron oxide particle size surface area ranges from 230 to 260        m²/gram.    -   The iron oxide pore size ranges from 10 to 90 angstroms.    -   The iron oxide pore size is 41 angstroms.    -   The iron oxide compound is unhydrated.    -   The iron oxide compound is hydrated.    -   The horizontally rotating sorbent bed's outer perimeter is        composed of a membrane.    -   For the membrane, the aperture size ranges from 1 to 30 microns.    -   For the membrane, the aperture size is 10 microns.    -   The membrane fabric is polymeric.    -   The membrane fabric is nylon.    -   The membrane fabric is wire cloth.    -   The membrane is composed of sintered metal.    -   The horizontally rotating sorbent bed is housed inside a larger        secondary compartment.    -   Located at the top of the secondary compartment is an escaped        sorbent particle containment membrane.    -   The escaped sorbent particle containment membrane is a polymeric        membrane with an aperture of 1 to 10 microns.    -   The escaped sorbent particle containment membrane is a nylon        membrane with an aperture of 1 to 10 microns.    -   The escaped sorbent particle containment membrane is a wire        cloth membrane with an aperture of 1 to 10 microns.    -   The escaped sorbent particle containment membrane has a        horizontal surface area larger than the 2-dimensional horizontal        surface area at bottom of secondary compartment, where rotating        sorbent bed is located.    -   Located above the secondary compartment membrane is one or more        additional membranes, filters, and/or other sorbents, including,        e.g., alumina, zeolites, sulfur, and/or activated carbon.    -   A process of using an iron oxide sorbent, contained inside a        horizontally rotating drum, to filter air or fluid or gas or        water or liquid.    -   A process wherein metal and inorganic particles are removed from        the air or fluid or gas or water or liquid.

Appendices are added, with figures, as separate files, for betterdescriptions and more variations. For example, Appendices 1-5 (labeled“App1to5”) correspond to FIGS. 1-5, respectively. Appendices 6-10(labeled “App6to10”) correspond to FIGS. 1-5, respectively. Appendices11-14 (labeled “App11to14”) correspond to an actual prototype of deviceshown in FIG. 1, shown from different directions/views/angles, from 4directions, to show the details in 3D images/photos.

In one embodiment of the invention, we have a rotating drum or cylinder,with self-cleaning process, to agitate the particles in each rotation,to remove them from clogging on a corner on the drum, using bothrotation of the drum and also air pressure from bottom, i.e., angularmomentum exerted from the drum and linear momentum exerted from air orfluid coming in from the bottom. In one embodiment of the invention, thewhole assembly can be shaken from the base or table, with a small motoror step motor, on a clock cycle, to slightly move the table left-rightdirections or up-down positions, just a little bit, to disengage theparticles, as a way of self-cleaning, in one or multiple cycles ofrotation of the drum, per cleaning process.

In one embodiment of the invention, we have particles of 5 to 90 micronsin the drum to filter the contamination, with drum rotatinghorizontally, and air pushing from bottom, coming in. In one embodimentof the invention, we have metal mesh/fiber, for more duration (lesstears or breaks), and less clogging on the corners or edges, at e.g. 20micron mesh sizes. In one embodiment of the invention, we have 40 RPH(revolutions per hour) to 2 RPM (revolutions per minute) for rotation ofdrum, e.g. for gathering toxic material/metals.

In one embodiment of the invention, we have a huge area/volume orarea/diameter or area/size or cross-section/size or surface-area/size orarea/weight or area/mass, for ratio or relative value, compared to theindustry, so that we can capture the contaminants with a new freshsurface area in a large amount efficiently, reducing the cost andimproving the quality.

In one embodiment of the invention, we have multiple beds in drums [5]and/or regular filters [11] in parallel for higher output, or in series,for various size particles, or reduce the percentage of escapedcontaminants, or both. The multiple beds in drums can be back-to-back inseries, e.g. going from large mesh to smaller mesh, in different stagesfor filtering process, for various size/type contaminants (see FIGS.6-8).

FIG. 1 is for one embodiment, as an example, for the whole apparatus.FIGS. 2-5 are for embodiments, as examples, for the cross section of thebeds in drum. FIG. 6 is for one embodiment, as an example, for seriesconfiguration of beds in drums and filters or membranes. FIG. 7 is forone embodiment, as an example, for parallel configuration of drums andfilters or membranes. FIG. 8 is for one embodiment, as an example, forseries/parallel mixed configurations of drums and filters or membranes.

In one embodiment of the invention, we have changing bed in drum toclean up manually or by other means, or exchange it altogether with anew one, periodically.

Any variations of the above teaching are also intended to be covered bythis patent application.

The invention claimed is:
 1. An apparatus for filtering fluid, saidapparatus comprising: a cylindrical drum; wherein said cylindrical drumcontains iron oxide particles; wherein said iron oxide particles areonly sorbent used in said apparatus; wherein said cylindrical drumrotates horizontally; a motor; wherein said motor rotates saidcylindrical drum; a pump; wherein said pump pushes said fluid into saidcylindrical drum from a bottom of said cylindrical drum, through anopening in a support structure of said cylindrical drum; a secondarychamber; wherein said fluid is pushed up, out of said cylindrical drum,into said secondary chamber; a second filter; wherein said fluid ismoved through said secondary chamber into said second filter; whereinsaid secondary chamber is located on top of said cylindrical drum;wherein said second filter is located on top of said secondary chamber.2. The apparatus for filtering fluid as recited in claim 1, wherein saidiron oxide particles are nano-porous.
 3. The apparatus for filteringfluid as recited in claim 1, wherein said iron oxide particles have sizeranges from 5 to 90 microns.
 4. The apparatus for filtering fluid asrecited in claim 1, wherein said iron oxide particles have an averagesize of 21 microns.
 5. The apparatus for filtering fluid as recited inclaim 1, wherein said iron oxide particles have a size standarddeviation of 2 microns.
 6. The apparatus for filtering fluid as recitedin claim 1, wherein said iron oxide particles have a size standarddeviation of 10 microns.
 7. The apparatus for filtering fluid as recitedin claim 1, wherein said iron oxide particles have surface area rangesfrom 50 to 400 m²/gram.
 8. The apparatus for filtering fluid as recitedin claim 1, wherein said iron oxide particles have surface area rangesfrom 230 to 260 m²/gram.
 9. The apparatus for filtering fluid as recitedin claim 1, wherein said iron oxide particles have diameter pore sizeranges from 10 to 90 angstroms.
 10. The apparatus for filtering fluid asrecited in claim 1, wherein said iron oxide particles have diameter poresize of 41 angstroms.
 11. The apparatus for filtering fluid as recitedin claim 1, wherein said iron oxide particles are unhydrated.
 12. Theapparatus for filtering fluid as recited in claim 1, wherein said ironoxide particles are hydrated.
 13. The apparatus for filtering fluid asrecited in claim 1, wherein said apparatus comprises a membrane.
 14. Theapparatus for filtering fluid as recited in claim 13, wherein saidmembrane has an aperture size ranging from 1 to 30 microns.
 15. Theapparatus for filtering fluid as recited in claim 13, wherein saidmembrane has an aperture size of 10 microns.
 16. The apparatus forfiltering fluid as recited in claim 13, wherein said membrane's fabricis polymeric or nylon.
 17. The apparatus for filtering fluid as recitedin claim 13, wherein said membrane's fabric is wire cloth or sinteredmetal.
 18. The apparatus for filtering fluid as recited in claim 1,wherein said apparatus filters one or more of following contaminants:silver, arsenic, lead, sodium, magnesium, aluminum, potassium, calcium,titanium, manganese, cobalt, nickel, copper, zinc, or gold.
 19. Theapparatus for filtering fluid as recited in claim 1, wherein said fluidis one or more of following: water, air, gas, or liquid.